Semiconductor light emitting device and its manufacturing method

Abstract

A semiconductor light emitting device includes a semiconductor light emitting element ( 1 ), a resin stem ( 10 ) having a recess ( 7 ), and a projection ( 9 ) made of a light-transmissive thermosetting resin on the resin stem so as to cover the entire upper surface and continuous upper part of side surfaces of the resin stem to a predetermined depth. The recess is filled with a light-transmissive resin encapsulating element ( 5 ) to embed the semiconductor light emitting element, one end of an externally extended first lead ( 21 ) and one end of an externally extended second lead ( 22 ) electrically connected to first and second electrodes of the semiconductor light emitting element, and a bonding wires ( 4 ) connecting the second lead to the second electrode. The projection functions as a lens and is made by hardening a fluid-state resin in an encapsulating case mold. Since the projection extends over the upper surface and upper part of side surfaces continuous from the upper surface, it is firmly bonded to the resin stem with a high adherability.

What is claimed is:  
     
         1 . A semiconductor light emitting device comprising: 
 a semiconductor light emitting element ( 1 ,  1 ′,  1 ″);    a resin stem ( 10 ) having a first lead ( 21 ), a second lead ( 22 ) and a resin portion ( 10 A) partly covering said first and second leads, one end of said first lead and one end of said second lead being externally extended from said resin portion, and said resin portion having a recess containing said semiconductor light emitting element, the other end of said first lead electrically connected to a first electrode of said semiconductor light emitting element, and the other end of said second lead electrically connected to a second electrode of said semiconductor light emitting element;    a light-transmissive resin ( 5 ) filling said recess of said resin stem; and    a projection ( 9 ) made of a light-transmissive resin to cover the entire upper surface of said resin stem, said projection being extended down onto side surfaces of said resin stem to a predetermined distance from said upper surface to continuously cover the upper part of the side surfaces all around.    
     
     
         2 . The semiconductor light emitting device according to    claim 1    wherein said projection ( 9 ) forms a lens having a vertical axis aligned with a vertical axis of said resin stem ( 10 ), these center axes being aligned with a vertical axis of said semiconductor light emitting element ( 1 ).  
     
     
         3 . The semiconductor light emitting device according to    claim 2    wherein said resin stem ( 10 ) has at least one through hole ( 15 ) in the bottom of said recess.  
     
     
         4 . The semiconductor light emitting device according to    claim 2    wherein said resin stem ( 10 ) has at least one through hole ( 14 ) extending from the upper surface to the lower surface thereof.  
     
     
         5 . The semiconductor light emitting device according to    claim 2    further comprising a fluorescent element for converting light emanating from said semiconductor light emitting element ( 1 ,  1 ′,  1 ″) into different wavelength light.  
     
     
         6 . The semiconductor light emitting device according to    claim 5    wherein said fluorescent element is contained in said resin portion ( 10 A) of said resin stem ( 10 ).  
     
     
         7 . The semiconductor light emitting device according to    claim 5    wherein said fluorescent element is applied onto inner wall surfaces ( 8 ) of said recess of said resin stem ( 10 ).  
     
     
         8 . The semiconductor light emitting device according to    claim 5    wherein said fluorescent element is contained in a mounting adhesive applied onto the bottom surface of said semiconductor light emitting element ( 1 ,  1 ′,  1 ″).  
     
     
         9 . The semiconductor light emitting device according to    claim 5    wherein said fluorescent element is contained in said light-transmissive resin ( 5 ) filling said recess.  
     
     
         10 . The semiconductor light emitting device according to    claim 5    wherein said fluorescent element is contained in said light-transmissive resin forming said projection ( 9 ).  
     
     
         11 . A semiconductor light emitting device comprising: 
 a semiconductor light emitting element ( 1 ,  1 ′,  1 ″);    a resin stem ( 10 ) having a first lead ( 21 ), a second lead ( 22 ) and a resin portion ( 10 A) partly covering said first and second leads, one end of said first lead and one end of said second lead being externally extended from said resin portion, and said resin portion having a recess containing said semiconductor light emitting element, the other end of said first lead electrically connected to a first electrode of said semiconductor light emitting element, and the other end of said second lead electrically connected to a second electrode of said semiconductor light emitting element;    a light-transmissive resin ( 5 ) filling said recess of said resin stem; and    a projection ( 9 ) made of a light-transmissive resin to cover the entire upper surface of said resin stem, said projection being extended down onto side surfaces of said resin stem to a predetermined distance from said upper surface to continuously cover the upper part of the side surfaces all around;    wherein said recess of said resin stem ( 10 ) is longer in a first horizontal direction in which said first and second leads ( 21 ,  22 ) extend than in a second horizontal direction normal to said first horizontal direction.    
     
     
         12 . The semiconductor light emitting device according to    claim 11    wherein said first electrode of said semiconductor light emitting element ( 1 ′) is connected to said first lead ( 21 ) by a bonding wire ( 4 ), and said second electrode of said semiconductor light emitting element is connected to said second lead ( 22 ) by a bonding wire ( 4 ).  
     
     
         13 . The semiconductor light emitting device according to    claim 12    wherein said projection ( 9 ) forms a lens having a vertical axis aligned with a vertical axis of said resin stem ( 10 ), these center axes being aligned with a vertical axis of said semiconductor light emitting element ( 1 ).  
     
     
         14 . The semiconductor light emitting device according to    claim 13    further comprising a fluorescent element for converting light emanating from said semiconductor light emitting element ( 1 ,  1 ′,  1 ″) into different wavelength light.  
     
     
         15 . The semiconductor light emitting device according to    claim 11    wherein the center of a horizontal cross-sectional configuration of said recess of said resin stem ( 10 ) is offset from the center of a horizontal cross-sectional configuration of said resin stem.  
     
     
         16 . The semiconductor light emitting device according to    claim 15    wherein said second electrode of said semiconductor light emitting element ( 1 ) is connected to said second lead ( 22 ) by a bonding wire ( 4 ), and the center of a horizontal cross-sectional configuration of said recess of said resin stem ( 10 ) is offset from the center of a horizontal cross-sectional configuration of said resin stem toward the externally extending direction of said second lead.  
     
     
         17 . The semiconductor light emitting device according to    claim 16    wherein said projection ( 9 ) forms a lens having a vertical axis aligned with a vertical axis of said resin stem ( 10 ), these center axes being aligned with a vertical axis of said semiconductor light emitting element ( 1 ).  
     
     
         18 . The semiconductor light emitting device according to    claim 17    further comprising a fluorescent element for converting light emanating from said semiconductor light emitting element ( 1 ,  1 ′,  1 ″) into different wavelength light.  
     
     
         19 . A semiconductor light emitting device comprising: 
 a semiconductor light emitting element ( 1 ,  1 ′,  1 ″);    a resin stem ( 10 ) having a first lead ( 21 ), a second lead ( 22 ) and a resin portion ( 10 A) partly covering said first and second leads, one end of said first lead and one end of said second lead being externally extended from said resin portion, and said resin portion having a recess containing said semiconductor light emitting element, the other end of said first lead electrically connected to a first electrode of said semiconductor light emitting element, and the other end of said second lead electrically connected to a second electrode of said semiconductor light emitting element;    a light-transmissive resin ( 5 ) filling said recess of said resin stem; and    a projection ( 9 ) made of a light-transmissive resin to cover the entire upper surface of said resin stem, said projection being extended down onto side surfaces of said resin stem to a predetermined distance from said upper surface to continuously cover the upper part of the side surfaces all around;    wherein inner side surfaces ( 8 ) of said recess serve as reflective surfaces.    
     
     
         20 . The semiconductor light emitting device according to    claim 19    wherein said resin portion ( 10 A) of said resin stem ( 10 ) is made from a thermoplastic resin not less than 65 weight % and a filler agent not more than 35 weight %, said filler agent being a high reflective material containing titanium oxide, silicon oxide, and/or aluminum oxide, and titanium oxide occupying 10 to 15 weight %.  
     
     
         21 . The semiconductor light emitting device according to    claim 20    wherein said projection ( 9 ) forms a lens having a vertical axis aligned with a vertical axis of said resin stem ( 10 ), these center axes being aligned with a vertical axis of said semiconductor light emitting element ( 1 ).  
     
     
         22 . The semiconductor light emitting device according to    claim 21    further comprising a fluorescent element for converting light emanating from said semiconductor light emitting element ( 1 ,  1 ′,  1 ″) into different wavelength light.  
     
     
         23 . A method for manufacturing a semiconductor light emitting device comprising the steps of: 
 forming a resin stem ( 10 ) by integrally molding a lead frame ( 2 ) having first and second leads ( 21 ,  22 ) and a resin portion ( 10 A) such that said first and second leads are positioned in an end-to-end alignment in a recess formed in the upper surface of said resin portion;    mounting a semiconductor light emitting element ( 1 ,  1 ′,  1 ″) having first and second electrodes in said recess, and electrically connecting said first lead to said first electrode and said second lead to said second electrode;    injecting a fluid-state thermosetting resin ( 12 ) into an encapsulating case mold ( 11 );    dipping the upper surface of said resin stem and upper parts of side surfaces continuous from the upper surface into said fluid-state resin in said encapsulating case mold; and    hardening said fluid-state resin to form a projection ( 9 ) of a light-transmissive resin on said resin stem,    said projection covering the entire upper surface of said resin stem, and extended down onto side surfaces of said resin stem to a predetermined distance from said upper surface to continuously cover the upper part of the side surfaces all around.    
     
     
         24 . The method for manufacturing a semiconductor light emitting device according to    claim 23    wherein said resin stem ( 10 ) is oriented upside down when dipped into said second fluid-state resin ( 12 ) within said encapsulating case mold ( 11 ).  
     
     
         25 . The method for manufacturing a semiconductor light emitting device according to one of    claim 24    wherein said resin stem ( 10 ) is dipped into said second fluid-state resin ( 12 ) within said encapsulating case mold ( 11 ) to a depth where said lead frame ( 2 ) contacts the edge of the cavity of said encapsulating case mold ( 11 ).  
     
     
         26 . The method for manufacturing a semiconductor light emitting device according to    claim 24    wherein said encapsulating case mold ( 11 ) has a stopper ( 13 ) along the edge of the cavity thereof, said resin stem ( 10 ) being dipped into said second fluid-state resin ( 12 ) within said encapsulating case mold ( 11 ) to a depth where said lead frame ( 2 ) contacts said stopper.  
     
     
         27 . The method for manufacturing a semiconductor light emitting device according to    claim 24    wherein said resin stem ( 10 ) has a stopper, said resin stem ( 10 ) being dipped into said second fluid-state resin ( 12 ) within said encapsulating case mold ( 11 ) to a depth where said stopper contacts the edge of the cavity of said encapsulating case mold ( 11 ).  
     
     
         28 . The method for manufacturing a semiconductor light emitting device according to    claim 24    wherein said lead frame ( 2 ) includes plural pairs of said first and second leads ( 21 ,  22 ).  
     
     
         29 . The method for manufacturing a semiconductor light emitting device according    claim 24    wherein said encapsulating case mold ( 11 ) is a part of a case mold chain which includes a plurality of said encapsulating case molds aligned in a row.  
     
     
         30 . The method for manufacturing a semiconductor light emitting device according to    claim 29    wherein a plurality of said resin stems ( 10 ) are formed for individual lead pairs ( 21 ,  22 ) of said lead frame ( 2 ), and are dipped into corresponding individuals of said encapsulating case molds of said case mold chain ( 11 ).  
     
     
         31 . A method for manufacturing a semiconductor light emitting device comprising the steps of: 
 forming a resin stem ( 10 ) by integrally molding a lead frame ( 2 ) having first and second leads ( 21 ,  22 ) and a resin portion ( 10 A) such that said first and second leads are positioned in an end-to-end alignment in a recess formed in the upper surface of said resin portion;    mounting a semiconductor light emitting element ( 1 ,  1 ′,  1 ″) having first and second electrodes in said recess, and electrically connecting said first lead to said first electrode and said second lead to said second electrode;    injecting a first fluid-state thermosetting resin ( 5 ) into said recess to embed said semiconductor light emitting element and said first and second leads;    injecting a second fluid-state thermosetting resin ( 12 ) into an encapsulating case mold ( 11 );    dipping said resin stem into said second fluid-state resin within said encapsulating case mold by bringing said first fluid-state resin into touch with the second fluid-state resin in said encapsulating case mold;    hardening said first and second fluid-state resins to form a light-transmissive resin encapsulating element ( 5 ) in said recess and a projection ( 9 ) of a light-transmissive resin on said resin stem,    said projection covering the entire upper surface of said resin stem, and extended down onto side surfaces of said resin stem to a predetermined distance from said upper surface to continuously cover the upper part of the side surfaces all around.    
     
     
         32 . The method for manufacturing a semiconductor light emitting device according to    claim 31    wherein said resin stem ( 10 ) is oriented upside down when dipped into said second fluid-state resin ( 12 ) within said encapsulating case mold ( 11 ).  
     
     
         33 . The method for manufacturing a semiconductor light emitting device according    claim 32    wherein said resin stem ( 10 ) is dipped into said second fluid-state resin ( 12 ) within said encapsulating case mold ( 11 ) to a depth where said lead frame ( 2 ) contacts the edge of the cavity of said encapsulating case mold ( 11 ).  
     
     
         34 . The method for manufacturing a semiconductor light emitting device according to    claim 32    wherein said encapsulating case mold ( 11 ) has a stopper ( 13 ) along the edge of the cavity thereof, said resin stem ( 10 ) being dipped into said second fluid-state resin ( 12 ) within said encapsulating case mold ( 11 ) to a depth where said lead frame ( 2 ) contacts said stopper.  
     
     
         35 . The method for manufacturing a semiconductor light emitting device according to    claim 32    wherein said resin stem ( 10 ) has a stopper, said resin stem ( 10 ) being dipped into said second fluid-state resin ( 12 ) within said encapsulating case mold ( 11 ) to a depth where said stopper contacts the edge of the cavity of said encapsulating case mold ( 11 ).  
     
     
         36 . The method for manufacturing a semiconductor light emitting device according to    claim 32    wherein said lead frame ( 2 ) includes plural pairs of said first and second leads ( 21 ,  22 ).  
     
     
         37 . The method for manufacturing a semiconductor light emitting device according to    claim 32    wherein said encapsulating case mold ( 11 ) is a part of a case mold chain which includes a plurality of said encapsulating case molds aligned in a row.  
     
     
         38 . The method for manufacturing a semiconductor light emitting device according to    claim 37    wherein a plurality of said resin stems ( 10 ) are formed for individual lead pairs ( 21 ,  22 ) of said lead frame ( 2 ), and are dipped into corresponding individuals of said encapsulating case molds of said case mold chain ( 11 ).  
     
     
         39 . The method for manufacturing a semiconductor light emitting device according to    claim 31    wherein said first fluid-state resin ( 5 ) and said second fluid-state resin ( 12 ) are different resin materials.  
     
     
         40 . The method for manufacturing a semiconductor light emitting device according to    claim 31    wherein ultraviolet rays are irradiated onto said resin stem before said fluid-state resin ( 5 ) is injected into said recess ( 7 ) of said resin stem.